Inexpensive and widely available DNA micro-array technologies offer dramatically improved capabilities for capturing and recording large volumbes of raw gene expression data. Enhanced data visualization and data mining tools are essential to transform this data into new medical knowledge, including the influence of genetic variability on disease susceptibility and response to xenobiotic substances. The goal of this project is to create new Java-based data visualization and analysis software that can be widely distributed to accelerated the specific application of microarrays to studying the genetic/molecular basis of drug addiction vulnerability.